"There won't be such a sharp divide" in 2009 between fast-growing markets such as Abu Dhabi and those with declining rents such as London's West End, says Torto. Next year will see growth in occupancy costs--which averaged 8% among the 172 markets monitored in the survey--level off, he says.

And if the declines in occupancy costs from Q3 2007 to Q3 2008 were steeper in London and Tokyo than in Midtown, Torto says it may be that those two cities had a head start over New York City. "London's West End started to see an adjustment about a year ago," he says. However, even with a 17.2% decline in occupancy costs, the West End remains the world's most expensive office market at $248.66 per square foot, compared to $98.06 in Midtown.

London's city financial district saw an even steeper year-over-year decline of 18.9% to $148.16 per square foot, and Torto adds that prices of office buildings there are starting to fall along with occupancy costs. "That's not the case in New York, where you still have a buyer/seller gap and therefore no transactions as a result," he says. In Tokyo's Inner Central District, occupancy costs saw a 5.9% decrease to $184.26, while in that city's Outer District, the fall-off was 11.2% to $151.69 per square foot.